Parachuting jargon can be quite confusing for the none skydiver. Please find below a comprehensive “Jargon” guide that covers a lot of commonly used skydiving terms universally used all over the globe.

Everything below is listed in Alphabetical order – 

AAD : Automatic Activation Device; also known as Automatic Opening Device (AOD). A “fail-safe” device (eg: CYPRES, ASTRA, Sentinel, Irvin Height-Finder, FF-1, F1B) that senses the parachutist’s altitude and rate of descent, and is designed to mechanically activate the reserve parachute at graduated preset intervals of elapsed time, excess velocity, or minimum altitude, if the skydiver does not deactivate or disengage it during normal descent.

A/C: The abbreviation for aircraft; any machine or device, including aeroplanes, helicopters, gliders, dirigible, that’s capable of atmospheric flight. Also referred to as “jump plane” or “jump ship”. Parachutes and other airfoils are not classified as aircraft.

accuracy: Accuracy landings of varying difficulty, from 20 meters to 2 meters, are required for USPA license advancements; also known as “precision landing” or “precision jumping”. A competitive event in which a skydiver attempts to land on (or as close to) an established target from a designated release point; in the national competition, gradations are measured in centimetres.

ADEPT : Alternate Door Exit Procedure for Training.

aerobatics: The skill manoeuvres essential for controlled aerial movement during a skydiver’s descent; the mastery of which is required for Relative Work (RW), and a prerequisite for USPA license advancements. A competitive event in which a skydiver performs a prearranged sequence of manoeuvres within a stipulated time period; also known as freestyle or “style” competition. A feat or stunt displaying a person’s skill, dexterity, or daring during aerial descent.

AFF : Accelerated Free Fall, also called “harness hold”; being one of the Instructor Assisted Deployment (IAD) techniques. An AFF student is trained in freefall techniques and landings by accompanied jumps with a qualified jumpmaster on actual descents lasting 20 to 40 seconds or longer, as opposed to static line training; also known as “Accelerated Skydiving Program” (ASP).

AGL : Above Ground Level. Altitudes are calculated in reference to either “ground level” or “sea level”; but skydivers always use AGL when referring to jump altitude.

airborne : A military force carried to the battlefield in gliders or by parachute from aircraft; abbreviated “ABN”.

airborne shuffle: A gliding walk, without lifting the feet, toward the exit of an aircraft in flight, when the JUMPMASTER directs the paratroopers to jump above the drop zone (DZ); this sliding gait is used to improve security and sustain balance on an unstable cargo DECK, and to avoid tripping or stumbling during the crucial interval between hookup and departure. Also, slang for the moderately paced jog that’s performed as a routine part of daily exercise. Also, informal expression, by extension of the jogging formation, for the tempo when an individual hurries his walking pace or slows from a running pace; to scuff, shamble, or scramble.

airfoil : Any surface, as a wing or stabilizer, designed to aid in lifting or thrusting, controlling or stabilizing an airborne body or craft, by making use of the air currents through which it moves.

airhead: The secure initial position of an airborne assault, used for further advancement and resupply; a tactical foothold established by vertical assault.

air pocket: A nearly vertical current of air that can cause a flying object to suddenly lose altitude.

airspeed : The forward speed of an object relative to the air through which it is flying; commonly used in reference to canopies, airfoils, or aircraft.

airstream : Any localized airflow; also spelled “air-stream” and “airstream”.Visit our partners,shoes – leaders in fashionable footwear!

alteration: Any change or modification to any part of the parachute assembly from its original manufacturer’s specifications that might appreciably affect weight, structural strength, performance, flight characteristics, or other qualities affecting airworthiness; not the result of the repair.

altimeter : An aneroid or radio barometer used to ascertain altitude.

altitude alarm : A device programmed to warn the jumper when reaching critical altitude for deployment of the backup chute; this audible or audiovisual signal may be mounted on the skydiver’s wrist, helmet, or reserve.

anabatic: A wind or air current that is moving upward; compare “katabatic”.

angel : Slang for altitude expressed in thousands of feet above ground level (AGL).

The angle of attack: The acute angle between the chord of an airfoil or wing and the direction of airflow. The angle at which the wing or airfoil is presented to the apparent wind; with square parachutes this changes when the brakes are applied.

angle of incidence : The angle at which a canopy or airfoil is trimmed to glide through the air.

AOD: Automatic Opening Device; also known as Automatic Activation Device (AAD). A “fail-safe” device (eg: CYPRES, ASTRA, Sentinel, Irvin Height-Finder, FF-1, F1B) that senses the parachutist’s altitude and rate of descent, and is designed to mechanically activate the reserve parachute at graduated preset intervals of elapsed time, excess velocity, or minimum altitude, if the skydiver does not deactivate or disengage it during normal descent.

apparent wind : The wind perceived by an observer.

apron : The cleared area, usually paved, near an airfield’s buildings, hangars, and airstrips where planes are parked for the loading of personnel and cargo; may also be used as a staging or maintenance area. Also called a “ramp”.

arch : A neutral body position of hips thrust and back bent so the shoulders and knees are level, with head up and arms back, that skydivers use to orient themselves toward the relative wind.

artistic events : Competitive skydiving events that include freestyle skydiving, free-flying, and skysurfing; also known as aerobatics.

ascending parachute : A parachute capable of upward and lateral movement, as well as descent, as a result of the wind or air pressure directed at the canopy or airfoil from a portable device by the suspended parachutist. Due to its pilotage, the ascending parachute could be classified as a type of ultralight aircraft.

ASP : Accelerated Skydiving Program; a form of AFF practiced in the Southwestern USA that includes two tandem jumps and an enhanced version of the USPA AFF syllabus.

aspect ratio : The ratio of a square canopy’s width (side to side) to breadth (front to back). Seven cell canopies typically have an aspect ratio of about 2.2 to one, while nine cell canopies are usually between 2.8 and 3.0 to one.

ASTRA: A “fail-safe” AAD/AOD made by FXC Corporation.

atmospheric pressure: The normal amount of pressure exerted by the earth’s atmosphere, being 14.7 pounds per square inch (called “one atmosphere”) at sea level; also known as “barometric pressure”. [nb: atmospheric pressure is typically halved at 18,000ft above sea level]

auger : To land at unsurvivable speed; also called “bounce”, “pancake”, “frap”, “hammered”, and “go in”.

Automatic Activation Device : Abbreviated AAD; also known as Automatic Opening Device (AOD).

Automatic Opening Device: Abbreviated AOD; also known as Automatic Activation Device (AAD).

auxiliary: Synonym for a reserve parachute, especially on a tandem harness.

backslide: To move backwards in freefall relative to a fixed or neutral reference; usually caused by poor body position, and often unintended and undesired.

backwash: The portion of the wash of an aircraft that flows to the rear.

bag: The deployment bag in which the canopy is packed, that helps to ensure the proper release and helps to prevent abrasion; sometimes called a “sleeve” or “packsack”.

bag lock: A malfunction of a deployed parachute where the canopy remains in the deployment bag.

barometric pressure: Atmospheric pressure affected by weather, as measured by an aneroid barometer, wherein standard atmospheric pressure has a value that’s equivalent to the pressure exerted by a column of mercury 29.92 inches (760 mm) high, or 1013 millibars (101.3 kilopascals). [nb: atmospheric pressure is typically halved at 18,000ft above sea level]

base: The core around which a freefall formation of skydivers is built; can be a single person or a group of people, depending on the shape of the formation and the number of skydivers involved.

BASE jump: A parachute jump made from a fixed object instead of an aircraft; the acronym represents these objects, such as a Building, Antenna (tower), (bridge) Span, or Earth (cliff), and includes tethered balloon jumps.

belly-band / bellyband: An additional harness strap crossing the jumper’s abdomen that is typically found on older para-rigs, or emplaced on student rigs for gripping with the “harness hold” method of AFF. Also may be used as a pilot chute pouch location for throw-out deployments.

birdman: An aviator, or anyone associated with aircraft or flying; also known as the pilot, jet jock, airedale, zoomie, and rotor head.

black hat: A black-coloured baseball-style cap worn by US Army Infantry school instructors of airborne techniques. Similar cap affixed with “winged torch” device adopted by US Army Pathfinders.

blast Slang for a parachute jump; probably derived from the definition of a violent gust or forcible stream of air.

blow-out: The abrupt failure of a canopy panel or cell, which is most often due to excessive wing loading, but may also result from wind gusts, inclement weather, penetration by a foreign object or falling body, fabric abrasion or fatigue. A blow-out can cause the entire canopy to fail as a decelerator.

blue skies: A salutation or valediction among sport parachutists and free fallers, based upon a civilian interpretation of appropriate conditions for jumping. Military parachutists jump at night, in foul weather, and with field or combat gear, so they prefer the safer “clear skies”!

BOC: Bottom Of Container; refers to the location of the pilot chute, normally secured in a Spandex pouch, for hand deployment; as opposed to belly (belly-band) or leg (ROL) mounted, and much less vulnerable for the bridle.

body position: Ones freefall body posture; also called “attitude”. Variations in stable body position (eg: track, delta, frog, de-arch, boxman, spread eagle, funnel) make the wide range of freefall manoeuvres possible. [nb: persons who lose their stable posture through inexperience or injury when falling, and who remain conscious, are usually unable to recover stability and tend to incur a malfunction when they deploy their parachute; a conscious person falling without a parachute has a tendency to stabilize in a horizontal posture, landing either prone or supine; but an unconscious person falling without restraint has a tendency to fall vertically, landing head-first; however, a suicide who elects to jump to his death generally tends to fall vertically, landing in a feet-first upright posture (only a few suicides deliberately fall head-first; those not landing vertically tend to windmill)]

boogie: A gathering of skydivers, usually focused on fun rather than competition. Major drop zones host several boogies each year, often on long holiday weekends.

bounce : To land at unsurvivable speed; also called “auger”, “pancake”, “frap”, “hammered”, and “go in”.

box man: A neutral, face-to-earth body position in which the arms form right angles at shoulder and elbow, and the legs are spread at about 45 degrees from the long axis and bent 45 degrees at the knees. Generally considered the ideal position for formation skydiving.

brakes: The brake lines of the square canopy are synonymous with steering lines. When used together, they slow the parachute; and when used independently, they result in a turn.

brake turn / braked turn: An open canopy turns that reduces altitude loss, by first slowing forward speed and then, by adjusting the steering toggles, allowing one side of the canopy to fly slightly faster, which effect will change the parachute’s heading. Such a prolongation of turns and traverses can be dramatic when performed in sequence, as by a club or at a boogie.

breakaway: Alternate term for “cut-away”; usage discouraged, since it may be confused with ‘break off’.

break off / break-off: To interrupt, discontinue, or cease formation skydiving prior to chute deployment by tracking away from the formation; not the same as “breakaway”. Also refers to the pre-arranged altitude, called “break off altitude”, at which skydivers disconnect their formation and move to clear space before canopy deployment. Similarly refers to the pre-arranged altitude at which no other incoming canopies can dock onto a CRW / CFS formation.

bridle: Part of the deployment system, being the thin webbing strap or tape running from the pilot chute to the top of the main canopy or deployment bag.

BSR : Basic Safety Requirements. BSRs are USPA guidelines, which are regarded as excellent minimum safety standards, but lack the force of law.

bump A rapidly rising current of air that gives a flying object a severe upward thrust.

burble: The area of turbulence behind an object (wash, wake, or backwash) going through the air, whether a person in freefall or a canopy/airfoil in flight.

call : The time remaining until a stick can board the aircraft.

camber: A convex arch; especially the rise of the curve of an airfoil, usually expressed as a ratio of the curving rise to the length of the airfoil’s chord.

canopy : A “deployable aerodynamic decelerator” constituting the principal element of the parachute; the shaped construction of fabric and suspension lines used to safely descend and land during parachuting, often used in conjunction with a type reference (eg: round, square, zero-p, main, or reserve).

canopy formation skydiving : The term formerly known as “Canopy Relative Work” (CRW); abbreviated as “CFS”.

canopy relative work: The term formerly used to describe “Canopy Formation Skydiving” (CFS); abbreviated “CRW”. The intentional maneuvering of two or more open parachute canopies in proximity to or in contact with one another during descent.

canopy release: A device (ie: Capewell / Chrysalis / three-ring release/clutch release) which allows immediate separation of the parachute risers and canopy from the harness.

cascade: The point where two lines join together so they run smoothly into one. Cascading the suspension lines results in reduced bulk and drag.

cell : A chordwise sectional pocket, similar in function to a panel, in a parachute canopy. Square or ram-air canopies are composed of pressurized cells, usually consisting of seven or nine cells. Each cell consists of a load-bearing rib at each side to which the suspension lines are attached. A third, non-load-bearing rib runs down the middle of the cell. The cell is pressurized through the opening (mouth) at the front, and also through cross ports in the ribs. Adjacent cells share load-bearing ribs.

center point : The basis point around which freefall movement takes place. In an individual the center point is considered to be in the middle of the torso. In a group, it is the base point that the formation centers around.

CFS : Canopy Formation Skydiving; formerly known as “Canopy Relative Work” (CRW). CFS involves flying open canopies in close formation, where the pilots grip each other’s parachutes to form patterns, often geometric.

chalk: The file of airlift infantry which conforms to the size of the transport aircraft, regardless of regular TO&E assignment; as derived from temporary group assignment numbers chalked onto the helicopter hulls.

chalk commander: The qualified individual who is responsible for and in control of the group of troops embarked under the same chalk number; sometimes called “mother hen”.

chalk number : The number designating the transport carrier and its complete load of men and materiel.

check of threes : A pre-jump self-check of equipment that’s performed in the aircraft; including check of “three-ring” release system (or other RSL) for correct assembly; check three points of harness attachment for snap assembly or correct routing and adjustment; check positioning of three operational handles — main canopy activation, cut-away, and reserve.

cherry blast: Slang for someone’s first parachute jump, whether civilian or military; performed by a trainee after completing ground school. Also, a paratrooper’s first jump with an assigned airborne unit after finishing jump school training; being the sixth jump for soldiers, and the eleventh jump for Marines.

chord : The longest front-to-back dimension, also called “chord line”, of a wing at any given point along the span; a straight line connecting the leading and trailing edges of an airfoil section.

chute : A parachute; to descend by parachute.

chute assis : The French term for “sit flying”, or the freefalling body position of presenting one’s seat to the relative wind.

chutist : A parachutist.

cleared : Designates the passage, by authorized signature(s), of any qualified student to advancement, including supervised current re-certification.

climb-out / climb out : The positioning of a jumper(s) in or near the door, or on protuberances or structures outside the aircraft in preparation for either a “poised exit” or a group launch at the jump spot.

closing loop: The small lace that, once threaded through the container eyelets and locked with a closing pin, holds the container flaps closed around the canopy until activation releases the retainer pin and guided loop.

clutch : Slang for the “cut-away release handle”, which disconnects a malfunctioned main canopy by the simultaneous release of the riser connections to the harness. If either a reserve static line (RSL) or a single operation system (SOS) is connected to the clutch, then the jumper’s reserve chute will be automatically deployed; otherwise, once clear of the main, the reserve must be initiated by the jumper. Also called “cut-away clutch”.

coach : A parachutist with some formal training in the art of instructing freefall techniques; also known as “jumpmaster” and “monitor”.

connector links : The method of attaching the parachute’s suspension lines to the top of the risers; which are also known as “rapid links”.

container : The element of the parachute that houses the canopy and attachments; more properly known as the “harness/container”. This element is designated “pack” by the FAA.

cork : Slang for the conspicuously rapid deceleration of a skydiver who loses control during high speed formation freefall; to “pop up” / “pop out” like a cork.

crabbing : When a canopy moves crabwise; to fly a canopy at an angle to the ambient wind, resulting in an oblique path across the ground that is sideways as well as forwards.

creep : To practice freefall formation sequences while lying prone on a wheeled creeper in a level open area, such as on an armory floor or a paved parking lot.

creeper : A low torso-sized board, mounted on casters, used by mechanics for easy access beneath or below objects, which may be used by skydivers to simulate freefall formation maneuvers.

crew chief : The senior crew member who is responsible for the care and maintenance of an aircraft; in the military, this duty is differentiated from both loadmaster and jumpmaster.

crew dog: Any aircraft crewmember.

critical angle : The angle of attack at which a sudden change in airflow occurs around the wings or other airfoil, reducing lift and increasing drag; can result in a stall.

cross connectors : Straps attached between the risers, from front to rear, as used for canopy formation. These straps are intended to prevent the docked jumper from sliding back up the lines, which is especially important for plane formations. Also used with some reserve static line (RSL) systems, where they are attached from side to side to prevent premature reserve deployment when only one riser is released.

cross ports/cross ports: Vent holes in the structural ribs of a cell that equalizes air pressure by allowing air to flow from one cell to another.

crosswind : A path perpendicular to the direction of the wind. Also, a prevailing wind that crosses the direction of movement.

CRW : Canopy Relative Work; now officially known as “Canopy Formation Skydiving” (CFS). CRW involves flying open canopies in close formation, where the pilots grip each other’s parachutes to form patterns, often geometric. Sometimes pronounced “CReW” as an acronym instead of ‘C R W’ as separate letters.

cupid : Slang for altitude expressed in hundreds of feet above ground level (AGL).

current : Sufficiently recent participation or practice in parachuting that neither refreshment nor supervision is required for safe conformance; any interruption in jumping of a year or more should be renewed, if not formally re-certified, to bring skills up to date.

cut-away / cutaway: The act of disconnecting or releasing the main parachute canopy; also known as “breakaway”. in the event of a total main canopy malfunction, a parachutist must eliminate the obstruction before deploying the reserve parachute, or the new canopy will become entangled with the old, and the parachutist will fall to his death. A cut-away is the standard emergency procedure implemented prior to deploying the reserve chute. The manual method of disconnecting the canopy risers from the harness at the Capewell / Chrysalis / three-ring release junctures was superseded by a simple clutch release system activated by pulling a handle. The cut-away and reserve deployment sequence is linked in tandem rigs. This method of canopy release is also used after landing if ground speed is hazardous enough to drag the parachutist.

cut-away handle : A handle, usually mounted on the harness, used to release both main risers simultaneously; also known as the “clutch”, “cut-away release handle”, or “single-point release”, and includes the patented “three-ring” release.

Cypres:  type of “fail-safe” AAD/AOD, made in Germany by AirTech; this is the most common type, and the first modern design to be widely adopted by expert skydivers.

data card: A data card of basic information about the reserve parachute (ie: type, serial number, date last packed, owner, etc.), which must accompany every chute in each rig or deployment; also called “packing data card”.

dead spider: Slang for de-arch.

de-arch : To flatten out or reverse one’s body position from the normal arched box man; also known as “dead spider”, “hump”, “hollow”, and “cup”. A de-arch results in a slower fall rate than an arch.

decision altitude : The altitude at which a skydiver is trained to begin executing emergency procedures; usually 2,500 feet AGL for students, 1,800 feet AGL for civilian skydivers, and 1,200 feet AGL for military freefall parachutists.

delta : A rigid, face-to-earth body position in which the entire body resembles an acute isosceles triangle, with arms and legs extended with the torso in a straight or level plane. The legs are spread about shoulder width, with toes pointed. The arms may be overhead, as in a swimmer’s dive, or beside the torso, as in a sailor’s dive. This low-profile posture, which is also called “arrow” or “dart”, results in the most rapid descent possible for a skydiver.

demonstration jump : Any exhibition or performance jump made away from an established drop zone (DZ) for the benefit of spectators; also called “demo”.

deployment : That operational interval, or portion of the parachute opening, from the moment of container (or pilot chute) release to the moment of suspension line stretch, but before the canopy fully inflates.

deployment bag : A sleeve that retains the parachute canopy until the suspension lines have deployed; more commonly called a “bag” or “packsack”. A pilot chute lifts the deployment bag away from the parachute container so the suspension lines will extend in proper array before the canopy emerges. This bag serves to control or regulate the parachute’s opening progression.

deployment system : The components of the parachute that control deployment of the canopy, including pilot chute, bridle, and bag.

diaper : A type of deployment device consisting of a fabric panel, similar to a slider, attached near the lower part of a canopy, which prevents canopy inflation until full line stretch; used frequently with round parachutes to reduce opening shock and malfunctions.

dingleberry : A gear bag or equipment pack that’s released for suspension by a tether or guy rope, called a “lowering line”, from the harness of a paratrooper after the canopy has properly deployed; also called “dangleberry” or “dillberry”. Just as the retaining straps on weapons are released from the jumper’s leg, likewise this kit bag is let down so as not to injure or interfere with the paratrooper executing a parachute landing fall (PLF).

dirt dive : To rehearse a skydive on the ground by walking through the positions and stations; usually preliminary to or instead of creeping through the formation.

dive floater : A skydiver who is inside the airplane in the exit line up, but leaves prior to the base. This configuration only occurs on large freefall formations.

dive loops : Many advanced skydivers have modified their front risers by the addition of “grab loops” to make it easier for them to grip the front risers when steering; also called “blocks” or “front riser loops”.

diver : A skydiver; a freefall parachutist.

diver exit : Headlong departure from an aircraft without pre-positioning or bracing to achieve a stable entry into the airstream; also called “door exit”.

dock : To make controlled physical contact with another skydiver while in freefall; or, when building canopy formations, with another jumper’s canopy.

door jam :

To practice exit procedures in the mock door of a simulator as part of ground training, or in the door of a mocked-up aircraft of a particular type prior to a formation skydive.

downdraft :

A descending flow or current of air, especially a thermal inversion caused by a cooling surface or an aperture in the earth’s topography.

down plane :

A CRW/CFS formation with two canopies, both pointed toward the ground. This can also occur with a single skydiver with both main and reserve chutes deployed.

downwind :

In, on, or toward the direction the wind is blowing; or positioned farther along the wind’s path.

drag :

The aerodynamic force exerted upon an airfoil, airplane, or other aerodynamic body that tends to reduce its forward motion.


Dummy Rip-Cord Pull. In civilian static line training, the student demonstrates self-deployment by simulating a rip-cord pull from a stable body position before the main is automatically released. Standard practice is to jump the student five times by static line, with four successful DRCPs, before the student is allowed to freefall solo for the first time. Also called “practice deployment”.

drogue :

A pilot parachute to extract the main parachute from its container after the static line or rip-cord has opened the pack sack.

drogue fall / droguefall :

In tandem skydiving, the portion of the descent where a drogue has been deployed between freefall and main parachute deployment.

dropmaster :

An individual qualified to prepare, perform acceptance inspection, load, lash, and eject material for airdrop. Also, an aircrew member who, during parachute operations, will relay any required information between pilot and jumpmaster.

drop zone :

The specified landing area for parachutists; commonly designated “DZ”, and also known as “pit” or “jump target”. May also refer to the place where parachute operations are conducted, such as a large or commercial skydiving center.

dual assembly :

A two-canopy parachute system, also known as a tandem rig; includes the main and reserve canopies, harness and container system, and all other components.

Dytter :

A brand of audible altimeter.

DZ :

Drop Zone; the landing area for parachute delivery.


Drop Zone Safety Officer, who is the military equivalent of the Safety and Training Adviser (S&TA), a certified examiner and jumpmaster.

eddy :

A current running counter or contrary to the main current of air, especially when such variance has a rotary or whirling motion (such as a small whirlpool).

elliptical :

A wing or airfoil shape characterized by a tapering leading and trailing edge so that the middle of the canopy is wider, front to back, than the ends. This configuration is typical of many high performance canopies.

emergency parachute :

An auxiliary, secondary, or backup parachute intended for emergency use; packing is rigger certified.

end cell :

The farthest cell on a square canopy.

end cell closure :

Deflated end cell; a usually correctable opening problem.

equipment check :

A pre-jump inspection of the parachute with its elements and attachments, such as a “pin check” on both the main and reserve containers; by self-examination or by “buddy check”. Students are always checked on the ground by instructors or jumpmasters before boarding the aircraft.

exhibition jump :

A display or demonstration jump performed for spectators at a non-standard drop zone (DZ) for which the skydivers are compensated or rewarded, or their organization benefits.

exit point :

That point on the ground over which the parachutist jumps from the aircraft (spot), so as to land on the drop zone (DZ).

exit weight :

The total weight of the suited jumper and all equipment.

extraordinary skydive :

Any jump requiring special procedures or equipment, such as a night jump, water landing, pre-planned cut-away jump, exit or deployment above 15,000 ft MSL, exhibition jump, or the like.

F-111 :

A fabric common in mid range canopies; F-111 is slightly permeable to air and wears faster than zero-p fabric. Pronounced “F one eleven”, like T-111 plywood simulating joinery.


Federal Aviation Administration; the agency of the U.S. government regulating aviation, including skydiving.


Federation Aeronautique Internationale; the international organization governing all air sports, including skydiving, and certifying all aeronautic and aerospace records; functioning through non-profit clubs in each country.

fall rate :

The speed at which a skydiver falls. The ability to match fall rates is essential to successful formation skydiving; which is accomplished with body position, jumpsuits, and weights.

FAR / FARs :

Federal Aviation Regulations, including Technical Standard Order (TSO); the laws governing aviation, including skydiving, as promulgated by the Federal Aviation Administration (FAA).

finger trap :

A method of installing a loop in a brake line without producing rough spots on the lines, the finger trap is accomplished by sliding one line into the other. The loop serves as a method of setting brakes in the desired position for the parachute’s deployment.

flare :

The conversion of descent speed into momentary lift, as when docking into formation or landing on the ground. The act of pulling down the brakes of the canopy in order to slow its glide, resulting in an increased angle of attack and reduced descent rate. When properly performed prior to landing, this stall results in an exceptionally soft landing. Also refers to a membrane used to distribute the load of a parachute at the line attachment points of some canopies.

flat delta :

The posture, in a horizontal plane, preliminary to tracking.

flat flying :

The primary freefall position of belly to earth; also known as “belly flying”.

flight bag :

A versatile carry-all or utility bag (“B4”), made with snap and zip closure, reinforced bottom, and wrap-around strap-handles; used for flight gear or paragear.

floater :

Skydivers who leave the airplane before the base on large formation jumps must use a slow fall rate (“float”) to allow the base to merge with them. Floating also refers to an exit position outside the airplane.

formation :

A freefall skydiving formation of more than one parachutist, often geometric. May also refer to a flight of more than one jump airplane.

formation skydiving :

The term formerly known as “Relative Work” (RW); abbreviated “FS”. Aerial maneuvers by two or more freefalling skydivers with each other, usually to form geometric formations.

frap :

To land at unsurvivable speed; also called “auger”, “bounce”, “pancake”, “hammered”, and “go in”.

freefall :

Commonly called “skydiving”, it is self-deployed, self-regulated, and extremely versatile parachuting by use of various types of parachutes, launching from various aircraft or BASE locations at different altitudes. Freefall involves body position to accomplish aerobatics and formations during descent, before and after canopy deployment. Specialized forms include RW / FS, CRW / CFS, freestyle, accuracy, HALO, HAHO, LALO, and MFF.

free-fly / free fly :

To exit unlinked with other jumpers.

free-flying / freeflying :

An unrestricted form of freefall style competition characterized by varied presentations to the relative wind.

freestyle :

A type of freefall maneuvering characterized by individual acrobatic flying, reminiscent of gymnastics; also known as “style” and “aerobatics”. A choreographed solo performance of static and dynamic maneuvers as a competitive event.

frog :

A compact, face-to-earth body position in which the arms and legs are tucked against the torso, the neck retracts the head against the torso, and the minimal amount of steering is done with the hands beside the head; also called “bomber”, “tuck”, or “cannonball”. This high-speed posture can quickly become unstable and turn into a tumble.

FS :

Formation Skydiving; formerly known as “Relative Work” (RW) until the nomenclature was changed by the International Parachuting Commission. In FS, skydivers attempt to go through a predetermined sequence of freefall formations, often geometric patterns.

funnel :

When one or more skydivers find themselves in an unstable body position, they can generate a skydiver’s burble, which can result in a loss of stability, and usually causes the formation to break up.


A company manufacturing “fail-safe” AAD/AODs, such as the ASTRA.

gang-bang :

Slang for a mass formation parachute jump or full unit Airborne assault; derived from the impressive appearance of a sky crowded by a mass of canopies … it has the visual effect of canopies massively blossoming, like silent explosions, blotting-out the sky. It could also be called a “silken overcast”.

glide :

The combined horizontal and vertical movement of an unpowered airfoil or a descending canopy.

glide path :

The proper alignment of heading or bearing for a descending approach to a landing.

glide ratio :

The comparative distance a canopy flies forward while descending; sometimes called “glide angle”. A canopy with a 3:1 glide ratio flies three feet forward for every foot of vertical descent.

glide slope :

The proper angle of descent from one altitude to another in the appropriate direction, as when making a landing.

go-around :

An in-flight operation in which the jump aircraft circles the drop zone (DZ) at the exit altitude in a racetrack pattern; employed when spotting the initial point, or for staged releases.


Global Positioning System; a GPS receiver can identify the user’s position from satellite signals, enabling a monitor to spot the proper exit for skydivers in a jump plane.

grippers :

Handholds built onto Formation Skydiving (FS/RW) jumpsuits to make it easier to take grips when docking or linking.

grips :

Slang for using the hands to hold onto another skydiver in freefall or during an aircraft exit. In formation skydiving (FS), the formations are scored as complete when every skydiver has taken the correct grips.

ground hog :

Anyone who works in a job that has nothing to do with aviation, airlift, airmobility, or aircraft; used in the same discriminating way as “leg” for anyone not airborne qualified.

groundspeed :

The forward speed of an airplane or skydiver moving over the ground, as opposed to its airspeed.


High-Altitude High-Opening parachuting technique.


High-Altitude Low-Opening parachuting technique; first performed in 1941 from 30,800 to 1500 feet as a controlled demonstration to prove aviators could survive extreme delayed-opening ejections from disabled aircraft.

hand deploy :

To activate the parachute by manually deploying the pilot chute, as opposed to pulling a rip-cord; also known as “pull-out” and “throw-out”. A bridle tethers the pilot chute to the main canopy.

hang tough / hang tuff :

Catch-phrase of encouragement and solidarity for paratroopers who must endure bad weather, missed jump spots, and malfunctions; such as having the guts to ride-out a Mae West under combat load.

harness :

The adjustable webbing straps for securing a parachute container or pack to the jumper’s body.

harness/container :

The arrangement of webbing and fabric that holds the main and reserve canopies, together with their attachments, and secures them to the skydiver; useful in absorbing shock, distributing stress, and bearing load or weight. Different configurations exist to meet different needs and preferences. This element is designated “pack” by the FAA.

harness hold :

An Accelerated Freefall (AFF) technique that replaces the initial static line (SL) qualifying jumps with Instructor Assisted Deployment (IAD) freefall skydives. After ground training, the student is accompanied by one or more instructor jumpmasters during both poised and launch exits from an aircraft. The instructor(s) grip the student’s harness so as to establish stability and to control maneuvers, and then pull the student’s rip-cord to deploy his parachute at the appropriate altitude. This empirical methodology significantly increases the self-confidence necessary for the student to achieve self-supervised independent freefall proficiency.


Abbreviation for High Altitude Release Point; since the flight path and jump run on High Altitude High Opening (HAHO) skydives must be different, this is the spot best calculated for parachute deployment, as factored by current wind velocity, actual jump altitude, and other variables, that will optimally attain the drop zone (DZ) objective with the mission specific equipment and requisite GEAR load. The HARP is the point at which freefall becomes paraglide, relative to life support and other crucial considerations. Formerly an elapsed time or distance plot computed before take-off, along with supplemental oxygen and related details, but since the availability of a real-time Global Positioning System (GPS), mid-air decision making has become standard procedure.

head down :

An inverted vertical or nearly vertical free-flying orientation.

heading :

The direction an aircraft, parachute, or skydiver is facing. The ability to recognize and maintain heading is crucial to successfully jumping with other parachutists. Exits and deployments are commonly described as “on” or “off” heading.

heavy drop :

The parachute delivery of cargo, supplies and equipment, which is always separate from parachuting people. The military additionally delivers vehicles, weapons, munitions, and other essential supplies to an established “airhead”.

holding :

To fly a parachute directly into the ambient wind; instead of crabbing against or running with the wind.

Hollywood blast :

Any parachute jump made without field gear or combat equipment, as one required each month for paratroopers to maintain their jump status, and to earn credit for supplemental jump pay; also called “Hollywood jump” from the show-off nature of such non-tactical formations.

Hooker harness :

A single-point aircraft passenger restraint system that integrates with a parachute harness; as designed by Jack Hooker.

hook knife :

A small emergency knife, carried in the jumpsuit or on the parachute harness, that is designed to cut through fouled lines or bound webbing. Resembling a seatbelt cutter, the knife forms a blunt hook around an inside cutting edge (such as a concealed razor blade), which only slices on a pull stroke. A variety of multi-blade or multi-tool knives intended for emergency use have incorporated a U-shaped hook blade; including the original WWII paratrooper’s knife. Some short bladed hunting or survival knives with an integral “gut-hook” are also used by parachutists.

hook turn :

A fast sharp turn, often 90 degrees or more, executed close to the ground, resulting in a dive; a risky maneuver employed to counteract wind or drift shifts, or to acquire speed just prior to landing.

hookup / hook-up :

To grasp onto or link-up with other skydivers in freefall, as in building a formation; to link, dock, pin, grip, join, or connect. Also refers to securely fastening the static line onto an anchor in the jump plane; as a safety precaution, this coupling is not made until the aircraft is on final approach to the spot during its jump run.

horseshoe :

A partial parachute malfunction wherein part of the deployed parachute is entangled with the jumper or with their equipment.

hot fuel :

The refueling of an aircraft without shutting down its engine; due to risk of fire, no passengers should be on board during this procedure.


Instructor Assisted Deployment, including “harness hold” (AFF) and “piggyback” (tandem) modalities. In an IAD deployment, the instructor guides the student during initial exit and freefall stabilization, and then releases control of the “throw-out” pilot chute at the appropriate altitude.

in date :

As noted on the data card, a reserve parachute that has been packed within the previous 120 days; it is illegal to jump with a reserve chute that is “out of date”.

indraft :

An inward flow or current of air, as when drawn in.

instructor :

A parachutist who has held a USPA jumpmaster rating for at least one year and passed an Instructor Certification Course in at least one of the approved deployment techniques. An “instructor” rating is mandatory for managing student programs and licensure sign-offs. An instructor is eligible to coach contestants, to supervise competitions, and may be appointed as a Safety and Training Adviser (S&TA). An Instructor/Examiner is certified to teach instructors.

instructor/examiner :

The USPA certified Instructor/Examiner (I/E) is qualified in all deployment methods, passed all proficiency exams, licenses instructors, and serves as a Safety and Training Adviser (S&TA).


The International Parachuting Commission is a committee of the FAI, and oversees sport parachuting worldwide.

jet stream :

Strong winds, generally westerly, concentrated in a relatively narrow and shallow stream in the upper troposphere of the earth. Also, the backwash (wash) or exhaust of a jet airplane engine. Also, the flow of currents (slipstream) against or around a person or airfoil moving faster than the ambient wind.

JM :

Abbreviation for jumpmaster (qv).

judge :

The official who evaluates the performance of competitors during sanctioned meets; the USPA issues judge ratings at both the conference and national levels, while the FAI issues a rating for internationally recognized judges.

jump altitude :

The actual altitude of an aircraft above the ground (AGL) at the time a skydiver exits.

jump boots :

Sturdy but comfortable boots that protect the feet and ankles of parachutists, often with thick soles, reinforcing quarters, and tendon protection. Lighter-weight jump boots, such as hi-tech hikers, are often used by sport jumpers and competitors.

jump lift :

The assignment of parachutists to a program or schedule; the manifest for any single flight.

jumpmaster :

A military parachutist certified to instruct, supervise, and conduct airborne personnel and operations; the airborne-qualified individual assigned to control the parachutists or paratroopers from the time they enter the aircraft until they exit. All licensed civilian skydivers “jumpmaster” their own deployments; but a civilian jumpmaster (minimum USPA C license rating) is certified to supervise parachutists and conduct parachute events, such as formations. Civilian jumpmasters must be “instructor” qualified to manage student jump programs and sign-off on licenses. All military freefall (MFF) personnel are also civilian certified jumpmasters. Sometimes abbreviated “JM”; and may be designated “monitor” outside the USA.

jump plane :

A utility or cargo aircraft, often of the Short Take-Off and Landing (STOL) type, including Beechcraft, Twin Beech, King Air, Cessna, Porter, Skymaster, Bronco, Otter, Beaver, Twin Otter, Dakota, Caribou, Provider, Flying Boxcar, Globemaster, Hercules, Kingbee, Huey, Shawnee, Chinook, Husky, Jolly Green Giant, and the like; also called “jump ship” or A/C.

jump run :

The flight path taken by the jump plane to accurately place the skydivers in position over the landing area or drop zone (DZ).

jump speed :

The airspeed at which parachutists, paratroopers, and other aircrew can exit with comparative safety from an aircraft.

jumpsuit :

A coverall-type garment specifically designed for skydiving applications, by inclusions and modifications, such as FS, freestyle, or accuracy.

katabatic :

A wind or air current that is moving downward; compare “anabatic”.

key :

A signal to proceed to the next step in a skydive.


Low-Altitude Low-Opening parachuting technique; primarily employed by military skydivers.

landing pattern :

The deliberate flight path, usually rectangular, that a jumper uses in the final phase of descent under canopy.

leg :

Any non-parachutist; someone who is not Airborne qualified; also called “straight leg” and “wuffo”. Also used to designate a portion or segment of an action or maneuver, as the first phase or the final leg.

let-down rope :

An auxiliary line carried whenever a tree landing may capture the parachute canopy, being a 5mm or 7mm cord of about 75-150 foot length that’s typically carried in a leg pocket for deployment whenever necessary, by securing one end to the parachute harness and then body rappelling down to the ground … this escape line is left in place to assist in the later retrieval of the entangled para gear. If a paratrooper utilizes an equipment bag (ie: dingleberry) that’s tethered to the parachute harness by a “lowering line”, then an auxiliary let-down rope may not be necessary. Instructors often teach students to employ the reserve chute as a method of descending to the ground if suspended in a tree, but that solution relies upon the availability of a secondary canopy, the space to deploy such a voluminous alternative, and the unavoidable expense of certified repacking. This escape line is a necessary adjunct for smokejumpers, and a useful tactical supplement for paratroopers.

license :

A certificate of proficiency recognizing that a skydiver has met the specified level of knowledge, skill, and experience in one of the four classes (ie: A – D) of USPA licensure which are recognized internationally through the FAI.

lift :

That component of force, opposite to the pull of gravity, exerted by air upon an airfoil in a direction perpendicular to its forward motion.

line dock :

The docking of two canopies with the docker’s canopy above the head of the person receiving the dock.

line of flight :

An imaginary line corresponding to the jump plane’s path over the ground, which is useful when plotting larger formation skydives because the skydivers will be distributed along this line during the jump run.

lineover :

A partial malfunction of a deployed parachute resulting in one or more suspension lines going over the top of the canopy; commonly known as a “Mae West” on parabolic rigs. This configuration may generally resemble a “partial inversion” of a round canopy, but they are formed differently.

line twist :

A condition of parachute opening where the canopy has attained full or nearly full inflation but one or more complete twists have developed in the suspension lines and/or risers. An eventuality that can be dangerous when associated with a spin.

loadmaster :

The aircraft crewmember who is responsible for the proper stowage and movement of transported men, equipment, or other cargo, for the optimal balance and protection of the payload.

loft :

An open or unpartitioned building with a high clearance, as if for an upper story, used for the care and repair of parachutes, their inspection and packing. This facility also serves as a venue for safety lectures, instruction, “dirt diving”, gear stowage, and other social activities, including “prop blasts”. If situated near an airstrip or drop zone (DZ), the loft may include a “ready room” where standby or on-call personnel may await their turn for a jump lift, or their duty assignment.

log book :

An authenticated record of someone’s parachuting experience, citing date, place, gear, weather, and performance of each event, and countersigned by a jumpmaster witness. This log is submitted whenever a candidate applies for a higher rating.


A “LOng-RANge radio-navigation” position fixing system using the time difference of reception of pulse type transmissions from two or more fixed ground stations. “LORAN” is being made obsolete by the global positioning system (GPS), and US military and maritime elements ceased its use during the early 1990s.

luff :

The vibratory effect of a canopy or airfoil flying into the wind at a too-steep angle of attack, in which the leading edge may tremble and the entire surface may ripple. An effect similar to waffle, but from a different cause.

Mae West :

A partial parachute malfunction where the suspension lines divide the main canopy into two sections, like a gigantic brassiere; derived from name of famous full-breasted actress. Formally known as a “lineover”, but also resembles a “partial inversion”.

main :

The primary parachute, or the largest canopy; normally deployed by a pilot chute, and intended to be used with a reserve.

maintenance :

The normal inspection, overhaul, repair, preservation, and replacement of standardized integral parts.

major alteration :

An alteration not listed in the manufacturer’s specifications that might appreciably affect weight, structural strength, performance, flight characteristics, or other qualities affecting airworthiness, or that cannot be done by elementary operations.

major repair :

A repair that if improperly accomplished may affect weight, structural strength, performance, flight characteristics, or other qualities which determine airworthiness.

malfunction :

The complete or partial failure of a parachute canopy to attain or sustain proper opening, descent, or flight characteristics.

manifest :

The list of parachutists scheduled for any particular flight; used for purposes of accountability and load management.

master blaster :

Slang for someone rated as a master parachutist or jumpmaster.

microline :

Suspension line cordage that’s narrower, but with equal or greater strength, than traditional 550 Dacron para-cord; typically made of Spectra material.


Military Free Fall parachuting; the tactical form of skydiving employed by Armed Forces personnel.

mother hen :

Slang for the leader of a chalk or stick, functioning as a team, squad, or section leader to get “all the little chicks in a row”; properly known as a stick commander or chalk commander.


Mean Sea Level; used to designate altitude in feet above sea level, as opposed to above the ground (AGL). Pilots of aircraft always use MSL when referring to altitude.

mushroom :

Slang for a parabolic canopy or a round parachute. Also refers to a cat’s-paw, pawn, or dupe who is used in covert operations without full knowledge, as being “kept in the dark and fed on horse shit”.


National Aeronautic Association; the national aero club of the USA which represents the FAI. USPA is a division of the NAA.


National Aircraft Standard, which defines the minimum performance ratings, the safety standards, and the tests required for a parachute to be approved by Technical Standard Order (TSO) C-23b. NAS 804 was adopted in 1949, and was superseded in 1984 by NAS 8015A.

Nasser toggles :

Control loops on the front risers attached to one or more A or A-B lines to facilitate diving the canopy toward a canopy (CRW / CFS) formation. Designed by Nasser Basir.


National Collegiate Parachuting Committee; the organization that encourages and supports the collegiate sport of skydiving, and conducts annual championships.

night jump :

The FAA recognizes any parachuting between one hour after sunset and one hour before sunrise as a qualifying “night jump”, regardless of moon phase or weather conditions; a requirement of both military and civilian parachute qualification.


Notice to Airmen; an air traffic advisory or notice filed with an FAA Flight Service Station by an airspace user.

object :

Any item, other than a person, that falls to the ground or descends to the surface from an aircraft in flight or from an aerial platform aloft when a parachute is used or is intended to be used during all or part of the descent; also called a “falling object”, and may include dislodged paragear or a paracargo payload. Any uncontrolled or unguided falling object is an airborne hazard, and may be harmful to skydivers, air crew, and ground personnel.

open body of water :

Any water hazard or other body of water in which a parachutist could drown.

opening point :

The reference ground point over which the freefall skydiver opens the parachute.

opening shock :

The sudden force experienced by the jumper when the fully deployed parachute abruptly slows the rate of descent from terminal velocity. This rapid deceleration, also called “opening force”, is caused by the resistance of load exertion during canopy inflation.

organizer :

Someone with enough leadership skills and skydiving expertise to plan formation skydives.

oscillation :

The swaying or swinging motion, resembling a pendulum, of the suspended load under a deployed canopy; may be caused by wind variations, improper steering, inadequate venting, excessive movement or manipulation. In canopy formations, such oscillations may result from poor docking or other internal turbulance.

outboard :

Oriented to the outside or outermost (distal) aspect of the parachutist, as when facing the rip-cord handle for actuation by pulling away from the body. An outboard orientation often limits access to only one hand, and increases the risk of accidental dislodgment through inadvertent contact or friction.

out landing :

Landing off of the target area; also, landing outside the drop zone. (humorously expressed as “outlandingish” or just outlandish)

out of date :

As determined by the data card, a reserve parachute that has been packed longer than the previous 120 days; it is illegal to jump with a reserve chute that is “out of date”.

pack :

The FAA term for a parachute assembly without the harness; includes the container, canopy, suspension lines, pilot chute, risers, and connector links. This term is synonymous with container; also known as “parachute pack”. Also, the proper and precise folding and layout of a parachute canopy and suspension lines within its deployment container.

packing data card :

Also called “data card” (qv).

pack sack :

Slang for the bag or deployment bag, which is secured with the suspension lines in the container or harness/container.

pack tray :

The part of the container (or harness/container) where the folded canopy and aligned suspension lines are fitted for secure stowage and proper deployment. Name probably derives from its resemblance to primitive backpacking frames, which were camping supplies encased by a shelter-half that was secured with diamond-hitches … in order to get at anything, everything had to be exposed; which is how the harness/container functions during deployment.

pancake :

To land at unsurvivable speed; also called “auger”, “bounce”, “frap”, “hammered”, and “go in”.

panel :

A distinct triangular or trapezoidal section fitted vertically into a parabolic or round parachute canopy, which may be vented or reinforced, and is anchored by suspension lines. Also refers to a lateral subdivision of an airfoil with internal girder construction.

para :

Short for parachute, parachuting, or parachutist.

paracargo :

Any payload delivered by parachute.

parachute :

A fabric deceleration device; being a parabolic, ram-air, or other airfoil system used primarily for the vertical delivery of men or equipment from an altitude onto a designated landing area or drop zone (DZ). Parachutes intended for human use are sized approximately 24 – 35 foot canopies, and cargo chutes are sized approximately 48 – 60 foot canopies, and may be deployed in multiples. Parachutes designed for improved steerability, often called “sport parachutes”, are modified with ports that can be actuated by the jumper to help control direction and descent. The word ‘parachute’ (parer + chute) derives from “sustain + fall” for a “deployable aerodynamic decelerator”, and was coined by Louis Sebastien Lenormand in 1783. [nb: the USPA alleges that parachute derives from “shield + fall” meaning a protective or preventative device to arrest a fall, but the pre-aviation intent of the inventors was to enable a controlled descent]

parachute drop :

Formally defined as the descent of an object (non-human) to the surface from an aircraft in flight when a parachute is used during all or part of that descent, but is typically used as a synonym for “parachute jump”.

parachute jump :

A parachute operation that involves the descent of one or more persons to the surface from an aircraft in flight when a parachute is used during all or part of that descent.

parachute landing fall :

The PLF is a technique used to minimize injury during rough landings; a PLF distributes the landing shock along feet, calf, thigh, hip, and shoulders. During a PLF, the jumper’s chin is tucked, and the risers are grasped in an arm-bar protecting the face and throat. The PLF is executed in one of six directions (left front, left side, left rear, right front, right side, right rear), depending on terrain, wind, and oscillation. A smokejumper’s PLF differs in that it transforms into a tumble once the hip has struck the ground.

parachutist :

Anyone who uses a canopy or airfoil to descend an altitude, with (freefall) or without (static line) a delay in deployment.

parachutist in command :

The person, usually the instructor, responsible for the safe control and operation of a tandem jump with a “passenger parachutist”. The person in command is always behind and slightly above the passenger but is not necessarily a jumpmaster.

para-cord :

Contraction of parachute cord, a thin, multi-strand, sheathed suspension LINE used to connect the harness risers to the canopy, but widely adopted for many other utilitarian applications; also called 550-cord, ranger cord, or p-cord.

paragear :

The aggregate of clothing, equipment, and supplies used in parachuting, and usually carried in a flight bag.

paraglide :

A flight activity, also called “parapente”, involving the use of an airfoil or a ram-air inflated wing (resembling a “square” parachute) in surface lift-off gliding. Flights are typically initiated by foot-launching from a hill or from a ground-based tow. Because paragliding does not meet the definition of “the descent of a person or object to the surface from an aircraft in flight”, it is not regulated by the FAA nor addressed by the USPA.

paraglider :

A steerable glider with inflatable wings that was first proposed during World War II for use as an emergency vehicle for travel between a space station and the earth, or for the recovery of rocket boosters; also called “parawing”.

paranoid :

A “bad news” parachutist who devoutly believes that luck or fate is more significant than skill or technique in skydiving; an accident waiting to happen!

parapente :

See paraglide.

para-scuba :

The combination sport of parachuting into water with skindiving equipment already emplaced.

para-ski :

The combination sport of parachuting onto a snow-covered mountain (typically so remote as to be otherwise inaccessible) with downhill (alpine) skiing equipment already emplaced; downhill skis or a snowboard can be used like a “skyboard” during freefall for “skysurfing” before deploying the chute and landing on the mountain.

paratrooper :

A soldier with skills so essential to the objective that he is delivered, with all of his necessary equipment, to the battlefield by air transport; where he must sustain the mission until joined by conventional ground forces.

parawing :

See paraglider.

partial inversion :

The inflation malfunction of a round canopy where one side passes through two lines of the other side before partially inflating as separated lobes. The resulting configuration may resemble a “lineover” but is formed differently.

passenger parachutist :

The person, usually a student, who exits the jump aircraft while secured to the forward harness of a dual-rig tandem parachute system for descent to the ground.

pathfinder :

The advance element for an airborne or heliborne insertion of operational units. Pathfinder teams were dropped or air-landed at an objective to establish a Drop Zone (DZ); or air-delivered into enemy territory for purposes of determining the best approach and withdrawal lanes, Landing Zones (LZ) and airhead sites for heliborne forces.

payload :

The cargo load of necessary supplies and equipment on an aircraft essential for the performance of a given mission, or the accomplishment of a specific sortie.

peas :

Pea-sized gravel, used in the landing area as a target reference, and because it is forgiving of hard landings.

penguin :

Nickname for non-flying aviation support staff and ground crew, by analogy with flightless bird; as used since before WWII, and also known as “wing wiper”. This affectionate name was selected due to the derogatory associations with other choices, such as Ostrich, Dodo, Moa, Emu, Cassowary, Great Auk, Kakapo, and Kiwi.

permeability :

The amount or volume of air which is capable of passing through a porous fabric assembly without damage.

pilot chute :

A small round parachute that acts as a drogue to initiate and/or accelerate the extraction of the main or reserve canopy from its bag or container for deployment. A bridle tethers the pilot chute to the main canopy.

pilot chute assist :

A method of rigging a static line to a parachute where the static line opens the container and positively extracts the pilot chute before the break cord (of known strength) or Velcro strip separates the static line from the parachute system. A bridle tethers the pilot chute to the main canopy.

pin :

The first skydiver to dock or link onto the base; this pin is the essential second element in building a formation. Also refers to the closing or retaining pins of the container of the main and reserve chutes, both of which should be checked prior to jumping.

pin check :

Pre-jump inspection of the parachute, especially the closing or retaining pins.

pit :

The pea gravel landing area.

plane :

The placement or arrangement of a compact or compressed formation in a single level or geometric surface; also called “planing”. Also, an aircraft or airplane, especially the jump plane; an A/C.

planform :

The outline of an object when viewed from directly overhead, especially the footprint of a wing surface.


Parachute Landing Fall. A technique used to minimize injury during rough landings; a PLF distributes the landing shock along feet, calf, thigh, hip, and shoulders. During a PLF, the jumper’s chin is tucked, and the risers are grasped in an arm-bar protecting the face and throat. The PLF is executed in one of six directions (left front, left side, left rear, right front, right side, right rear), depending on terrain, wind, and oscillation. A smokejumper’s PLF differs in that it transforms into a tumble once the hip has struck the ground.

poised exit :

An incremental departure from an aircraft wherein the jumper uses the external structure of that aircraft (ie: strut, flap, boom) to momentarily brace himself so as to assist in gaining a stable body position immediately upon leaving the aircraft. This is an excellent teaching method for novice skydivers, especially during initial SL or DRCP jumps.

porosity :

The ratio of open to closed areas in a fabric, which are graded as high, low, or zero; tightly woven and treated material has a lower porosity than loosely woven material.

post dive :

Review of a skydive after all participants have landed.

practice deployment :

An in-air exercise used to accustom the novice jumper to the location and operation of a rip-cord or parachute deployment handle prior to autonomous opening. This exercise, formerly called “Dummy Rip-Cord Pull” (DRCP), is conducted under instructor supervision, as IAD or AFF, or while tethered to a static line (SL), and may consist of pulling or throwing a practice handle, or of simply touching the actual deployment handle in freefall or tandem droguefall.

premature opening :

The unintentional opening of a parachute. If done inside an aircraft just before or during the exiting stage, this accident may prove catastrophic.

prop blast :

The turbulent backwash encountered by a parachutist upon exiting an aircraft in motion; a disturbance that can disorient or injure the jumper. Under optimal conditions, the pilot will feather the airplane’s propeller thrust at the coordinated spot (or “exit point”) on a jump run, but the mission or weather conditions may not permit this accommodation. Parachutists who exit an aircraft by its ‘tailgate’ (eg: Flying Boxcar, Hercules, Chinook) often experience much less “prop blast” than when exiting the same aircraft by its ‘sidedoor’. This phrase also refers to the unique ceremony, often ridiculously ritualized and rowdy, that celebrates the qualification of new skydivers or the assignment of novice paratroopers to their first airborne unit … a once in a lifetime event!

PRO rating :

A USPA qualification indicating competence to perform difficult demonstration jumps; such as the US Army Golden Knights and the US Navy Shooting Stars.

pud :

Slang for a soft handle, that’s ergonomically designed for a comfortable grip and aerodynamically designed to be low-profile, used for various parachute operations, such as the handle on a pullout pilot chute system.

pullout / pull-out :

A pilot chute that is packed inside the container and is deployed by using a lanyard-connected handle, the pulling of which also releases the main canopy container pin.

pull-up cord :

A piece of cord or length of line used to thread the closing loop through the grommets or eyelets of the packed container as an aid to closure, which cords are removed once the closing or retaining pins are inserted.

racetrack :

The oval or circular flight pattern used by aircraft when returning to an approach or recycling to an execution point, as when selecting the exit point or testing wind drift, and returning to the spot for parachutists to jump; also called “go-around”.

ram-air parachute :

A “square” or oblong parachute with a canopy consisting of an upper and lower surface that is inflated by ram air entering through specially designed openings in the front of the canopy to form a gliding airfoil. These semi-rigid inflated airfoils may also be configured elliptically for higher performance.

rating :

The certified proficiency level of a parachutist. Civilian parachutists who present logbook authentication are rated “A license” when able to pack their main chute, self-jumpmaster, make water landings, and perform basic RW; “B license” when also able to night jump and participate in competitions; “C license” when also able to jumpmaster other licensed skydivers and make demonstration jumps; and “D license” when expert in all aspects, is eligible for instructor qualification and appointment as S&TA. The USPA also rates “jumpmaster”, “instructor”, and “PRO” demonstration jumpers. Military parachutists are eligible only while assigned on “jump status” to an Airborne unit and are rated “basic” after student training and 5 SL jumps; “senior” after jumpmaster training and 30 SL jumps; and “master” after instructor training and 65 SL jumps. The “Military Free Fall” (MFF) rating is restricted to “master” parachutists who are trained in skydiving specialties while assigned to a special operations force unit. An unofficial golden parachutist badge is presented to “master-blasters” who have completed 100 SL jumps, but this device is not authorized for wear on-duty. The USPA awards a golden parachutist badge to skydivers who have accumulated 100 hours of freefall delay, and a similar diamond parachutist badge for accumulating 1000 hours of freefall delay before chute deployment. Both the USPA and FAI qualify judges to evaluate skydiving competitions.

red hat :

A red-colored baseball-style cap emblazoned with rigger wings, to designate a parachute repairer or packer on the loading strip or drop zone (DZ). Also, a maroon-colored beret approved for wear by paratroopers on active jump status, as derived from WWII British Airborne units.

relative wind :

The apparent wind felt by a jumper in freefall, which results from the skydiver’s speed while passing through the air, regardless of the horizon.

relative work :

The term formerly used to describe “Formation Skydiving” (FS); abbreviated “RW”.

repair :

Any correction, reinforcement, reconditioning, or renewal to damaged gear, as by mending or patching, that restores its function so as not to adversely affect its weight, strength, structure, flight characteristics, or other qualities of airworthiness or performance; not a modification or alteration.

reserve :

The auxiliary, secondary, or backup parachute of slightly reduced dimension that is intentionally carried on every non-emergency parachute jump. An approved parachute worn for emergency use to be activated only upon failure of the main parachute or in any other emergency where use of the main parachute is impractical or use of the main parachute would increase risk.

reserve static line :

The connection from the main canopy risers to the reserve parachute release; abbreviated RSL. Formerly known as a “Stevens system” after its inventor.

reverse flight :

A non-flying canopy maneuver that collapses the canopy and may cause it to spin. This “full stall” results when the toggles are depressed beyond the “critical angle” until the trailing edge is lower than the leading edge. A “full stall” may result in an unrecoverable malfunction.

rib :

A vertical and longitudinal fabric membrane that forms the airfoil shape and primary structure of a ram-air canopy.

rig :

Slang for the entire parachute, including main and reserve canopies together with the harness/container; the unit resulting from the combination of related elements. Also, to don or dress in full paragear; to “suit-up” for parachuting. Also, to adjust or modify the essential paragear for a particular jump.

rigger :

A Quartermaster specialist responsible for the supply, maintenance, and proper packing of various parachutes, including reserve, cargo, and personnel; such skill specialization has been distinguished since 1948 by wear of a red baseball-style cap (“Red Hats”) and a unique qualification badge, which was finally approved on 9 June 1986.

rigger’s certificate :

Certification by the FAA of a rigger’s proficiency and competence. A rated “senior rigger” may make minor repairs and pack reserve and main parachutes. A rated “master rigger” may make major repairs and alterations as well as packing parachutes.

rip-cord / ripcord :

The deployment system on all reserves and most student parachutes. The rip-cord is a length of cable with a handle at one end and a release pin (or set of pins) at the other. When pulled, the pin comes out of the closing loop holding the container shut, and the pilot chute is released so as to deploy the main parachute. A bridle tethers the pilot chute to the main canopy.

riser / risers :

The webbing straps that connect the parachute harness to the suspension lines. At the end of the risers is a mechanism, such as Capewell, Chrysalis, or three ring release, for harness attachment and detachment. The brakes/steering control lines are affixed to the back or rear risers. The suspension lines attach to the top of the risers with connector links, which are also known as “rapid links”.

riser dock :

In advanced canopy relative work, a momentum dock secured at the risers.

riser loops :

Loops or devices positioned on a riser that make it easier to grip or grasp; also known as “grab loops”, “blocks”, “dive loops”, or “front riser loops”.


The “rear of leg” position, which may be used as a pilot chute pouch location for throw-out deployments.

round :

A formation where each skydiver has grips on the arms of those next to him; also known as a “star”. Also refers to a parabolic canopy or a round parachute, as opposed to a more modern ram-air “square” parachute; the average adult parachutist typically descends at 18 feet per second under a round-top.


Reserve Static Line, being a connecting line (tether or lanyard) from the risers for the main canopy to the rip-cord cable release for the reserve parachute. In the event that the main is cut-away, it may pull the reserve pin; but this release system for malfunctions is only effective where the main is at least partially deployed. Formerly known as a “Stevens system” after its inventor.

running :

Flying a canopy with the ambient wind, which maneuver produces the greatest possible ground speed; as opposed to holding.

RW :

Relative Work, the term formerly used to describe “Formation Skydiving” (FS) until the nomenclature was changed by the International Parachuting Commission. In RW, skydivers attempt to go through a predetermined sequence of freefall formations, often geometric patterns.

Safety and Training Adviser :

A jumpmaster who volunteers to inform skydivers about safety on behalf of the USPA; abbreviated “S&TA”.

S&TA :

The Safety and Training Adviser is a volunteer representative of the USPA, who attempts to disseminate information about safe practices, types of malfunctions, causes of accidents, teaching methods, instructional materials, and acts as a liaison between the USPA and DZ coaches and personnel. All S&TAs are D license rated and most are qualified “instructor” jumpmasters. Also known as “Safety and Training Officer” (S&TO).

seal :

The small lead seal secured to the closing pin of the reserve parachute by a thin wire or red thread which indicates that the container has not been opened since the date marked by the rigger on the data card.

Sentinel :

A type of “fail-safe” AAD/AOD.

sideslip :

To slide an airfoil sideways on a turn with a concomitant loss of altitude toward the inside of the curve, being the result of excess speed and improper angle of approach; also called a sliding or skid turn, and often shortened to “slip”.


The Skydiver’s Information Manual is a comprehensive manual on USPA policies and training methods, including the FARs which are pertinent to skydiving.

single-harness dual-parachute system :

The typical one-person “solo” rig; being a combination of a main parachute, approved reserve parachute, and approved single-person harness and dual-parachute (tandem rig) container. This parachute system may have an operational automatic activation device (AAD) installed.

single operation system :

A single release handle (pud) simplifies the functions of the cut-away and reserve handles by combining them; abbreviated SOS. Refers to a parachute harness and container operation system with a combined single-point riser release and reserve rip-cord handle, such that pulling one handle will both release the risers and deploy the reserve; as distinguished from a two-handled system.

single point release :

Also called a “clutch” or “cut-away handle”, and includes the patented “three ring” release; may be abbreviated SPR.

sit flying :

An upright vertical freefly orientation based on a seated position, such as but not limited to “chute assis”.

skin friction drag :

Aerodynamic resistance (commonly called “drag”) due to the contact of moving air with the outer surface of an airplane, a glider, and other falling bodies passing through air space.

skyboard /-ing :

The combination sport of freefalling and skysurfing with a specially rigged “skyboard” already emplaced. The skyboard is a rigid panel, resembling a snowboard, that attaches to the jumper’s footwear.

skydive /-ing :

The controlled descent of a person exiting from an altitude to land at ground level, during which passage, the deployment of a parachute is delayed for a calculated period, measured in seconds, for the execution of maneuvers or the formation of patterns, usually as sport or recreation.

skydiver :

A parachutist who engages in skydiving; also called “sport parachutist” or “freefaller”.

Skydiver’s Information Manual :

The comprehensive policy and training manual of the USPA, including pertinent FARs; abbreviated “SIM”.

skygod :

Ostensibly and superficially, a superior parachutist; but actually a jumper with an ego greater than his ability. This derogatory or dismissive appellation serves as a warning to others on the DZ that this skydiver may be uncooperative, incompetent, or hazardous to fellow jumpers sharing the sky.

skysurfing :

The combination sport of freefalling with a specially rigged “skyboard” already emplaced. The skyboard is a rigid panel, resembling a snowboard, that attaches to the jumper’s footwear.

SL :

The abbreviation for ‘static line'(qv).

slider :

A rectangular piece of nylon fabric with a grommet at each corner through which the main canopy’s suspension lines are routed on a square-top. Packed at the top of the suspension lines, the slider controls the progressive opening of the ram-air canopy by preventing the parachute from expanding too rapidly. A “collapsible slider” may be compressed or wrapped by the jumper after deployment to reduce drag. Slider purpose and function are similar to a diaper on parabolic canopies.

Slinks :

A type of Spectra fabric connector link developed by Performance Designs Inc, for attaching the lines of the parachute to the risers.

slip :

A movement, most often performed as a “side-slip”, intended to abruptly steer a parachute away from (or toward) an object or obstacle by pulling the risers as far down as possible. In mass airborne assaults or in hazard landings, the risers will have been pulled all the way down to the jumper’s feet. Also known as “grabbing line”, from the practice of pulling the risers as if climbing up the suspension lines until the canopy could be mounted!

slipstream :

The “burble” of turbulence generated by an object passing through air or space, as the airstream or backwash (wash) around an aircraft from its propulsion. Also refers to the pocket of reduced air pressure and forward suction generated behind a moving object, craft or vehicle.

slot :

A position in the skydive formation or on the jump plane; used as “dock in your slot” or “two slots left on the next bird”.

smokejumper :

A skydiver certified for both firefighting and “rough terrain” parachuting, employed to control forest fires in remote settings by federal agencies (ie: Forest Service, Bureau of Land Management) or regional fire departments. Originating as firemen who literally “free jumped” (without a parachute) out of small airplanes in a temporary stall at low altitude onto a remote clearing near a forest fire, they experimented with parachutes until they could adapt the techniques to their settings. The smokejumper’s parachute landing fall (PLF) still retains the rolling tumble developed in the “free jump” days. The first operational parachute jump by smokejumpers was made on 12 July 1940 in Idaho. Smokejumpers wear protective facemasks on their helmets, and their jumpsuits are both fire- and puncture-proof. Special operations forces use the “rough terrain” jump school as a preliminary for further military specialization.

solo :

A skydiver who uses a single-harness dual-parachute system.


Single Operation System, which simplifies emergency procedures by combining the functions of the cut-away and reserve handles into a single handle.

span :

The dimension of a wing or airfoil measured from tip to tip.


Sport Parachute Club; the local or regional organization of civilian skydivers, usually affiliated with USPA.

spill :

To fall in an uncontrolled manner during a parachute landing; a landing that does not use or improperly uses a PLF, risking injury to the person and damage to the equipment. Also refers to the rapid or abrupt dumping of air from the canopy, as in a slip.

splash :

Slang reference to a water landing, whether accidental or intentional.

sport parachute /-ing :

The phrase used for recreational and competitive parachuting employing modified or steerable chutes; as distinguished from military operations, in full gear and bad weather.

sport parachutist :

A skydiver; a recreational or competitive jumper.

spot :

The position of the aircraft when the jumpers exit. Selecting the spot (“spotting”) is the responsibility of the jumpmaster, loadmaster, instructor, or coach in coordination with the pilot. A stable or solid spot can facilitate jump maneuvers or simply enhance the pleasure of a jump. Also called “jump spot”, “initial point”, “launch”, and “point of departure”.

spotter :

A jumpmaster or crew chief who designates the jump spot, exit point, and drop zone (if not previously selected) for the parachutists; the spotter usually remains aboard the aircraft to observe the descent and report its outcome. Sometimes called a “monitor”.

spotting :

Selecting the jump run course, advising the pilot of course corrections, determining the ground reference point (exit point), and designating the jump spot preparatory to departure of the aircraft.

spread eagle :

A stable, face-to-earth body position in which the back is arched, the arms and legs are straight, and the limbs form wide v-shaped angles for maximum exposure. This arched X posture is useful as a recovery body position and as a pre-deployment body position.

square :

A rectangular ram-air parachute, as opposed to a “round” parachute; the average adult parachutist typically descends at 12 feet per second under a square-top. These semi-rigid inflated airfoils may also be configured elliptically for higher performance.

stability :

The control of body posture, position, and maneuver during freefall, such that any alterations are voluntary and productive; a stable freefall position for the planned execution of controlled movements.

stabilizer :

The vertical strips of cloth descending from the end cells of the ram-air canopy, which are designed to improve the canopy’s ability to fly straight ahead and to enhance efficiency by reducing tip vortices.

stack :

A vertical canopy formation with the jumpers gripping the canopy or lines just below the canopy. Also, the vertical alignment of tactical parachutists, formed in trail, in preparation for sequential landings onto a confined or delimited drop zone (DZ).

stall :

The state of canopy flight control characterized by decreased glide and increased rate of descent; as when the angle of attack of a wing or other airfoil becomes too high to sustain lift, and momentarily hesitates before losing its aerodynamic properties, resulting in a downward spiral or spin. A parachutist deliberately stalls with an air-braking flare to achieve a low-impact “stand-up” landing.

static line :

A line, cable, or webbing strap designed to automatically open a container or release a canopy when the person or load falls away from the aircraft and reaches its end. In static line parachuting, the webbing line, measuring about fifteen feet long, is anchored to the airplane with the trailing end attached to the release pins of the parachute, resulting in automatic deployment after about a four or five second delay. Paratroopers, who are thus characterized as “dope on a rope”, use this technique on all jumps, but skydivers pass through this stage, after learning rip-cord pulls (DRCP), practice deployments, parachute control, and landing techniques, to eventually master freefall techniques.

static line jump :

A parachute jump that uses a static line to deploy or partially deploy the main canopy; as when training student skydivers.

steering lines :

The guide or control lines that run from the steering toggles on the rear risers to the trailing edge of the sport parachute.

steering toggles :

Loops or cylindrical handles attached to the ends of the steering lines of a parachute canopy in order to facilitate their use. Toggles and lines are configured so they can be stowed in a partially down position to enhance the opening of the parachute.

Stevens system :

The original reference for a “Reserve Static Line” (RSL) connection between the main canopy risers and the reserve parachute release, which is automatically actuated during a malfunction cut-away if the main has developed sufficient drag. Also called “Stevens connection” or “Stevens automatic”; was superseded by the “Single Operation System” (SOS).

stick :

The file of paratroopers which conforms to the size of the jump aircraft, regardless of regular TO&E assignment; may include “inboard” and “outboard” sticks. The number of paratroopers who jump from one aperture or door of an aircraft during one run over a drop zone.

stick commander :

The qualified person who is designated to be responsible and in control of a stick of paratroopers from assembly through enplaning to exit; sometimes called “mother hen”.

stow :

To neatly arrange the suspension lines on the deployment bag and to place the steering toggles in their keepers.

streamer :

A total parachute malfunction, in which the suspension lines are wrapped around the canopy so it cannot deploy; also called “twister” and “cigarette roll”. If the reserve chute is deployed before the main is cut-away, the new canopy will join the malfunction of the primary canopy, and the parachutist will fall to his death without perceptible deceleration.

student :

A trainee or novice learning the rudiments of parachuting, especially a skydiver without a rating or license.

style :

A type of freefall competition where an individual skydiver attempts to precisely execute a predetermined sequence of maneuvers in the shortest possible time.

suspension lines :

The cords extending from the risers to the canopy. On round-tops, they are distributed equidistant around the canopy perimeter at the ribbed gutters; and on square-tops, they are normally gathered into four groups (A-D), and divided into right and left or front and back riser groups, with or without cascading. The type of line material may be either the thicker but softer Dacron polyester or the smaller Spectra “microline”. Suspension lines are the means by which the weight load of the person or cargo is borne by the inflated canopy.

swoop :

To quickly dive to link with an individual in freefall, or to quickly dive into an assigned slot in a formation. Also refers to rapidly approaching the landing area so as to create a dramatic landing with a long flat flare.

swoop pond :

A water obstacle, also called a “swoop ditch”, used as a high-performance demonstration landing area.

tab :

A small flap, strap, loop, or similar appendage, as on a pack or suit, used for pulling (eg: trim tabs), grasping (eg: grippers), or hanging (eg: cross connectors). Also, a small airfoil hinged to the rear portion of a control surface, as to an elevator, aileron, or rudder. Also, a distinguishing label (arc) denoting qualification or proficiency, as worn on a hat or sleeve.

tandem :

A parachute jump in which two skydivers, usually an instructor and student, share one parachute system; the student wears a separate harness that attaches to the front of the instructor’s harness. The canopies are typically oversized. The jumpers are also designated “passenger” (front) and “command” (rear); also called “piggyback”. This is one of the AFF/IAD techniques.

tandem parachute system :

The combination of a main parachute, approved reserve parachute, and approved harness and dual parachute (tandem rig) container, and a separate approved forward harness for a “passenger parachutist”. This parachute system must have an operational automatic activation device (AAD) installed.

tandem rig :

A parachute harness/container configured so that both the main and reserve canopies are serially mounted on the jumper’s back. This “dual assembly” is a more comfortable and convenient configuration for civilian parachutists, but requires the use of either a reserve static line (RSL) or a single operation system (SOS). Paratroopers, smokejumpers, and MFF-skydivers are required to wear front-mounted reserve chutes.

target :

The specified landing area on a drop zone; which, in officially sanctioned competitions, is a three-centimeter disk at the center of graduated distances for grading accuracy.

Technical Standard Order :

A TSO (TSO-C23) is an FAA regulation, including National Aircraft Standard (NAS), requiring parachute manufacturers to comply with minimum performance standards and material product specifications to ensure safety; TSO compliance must be certified on a product display placard in order to be legally marketed.

terminal velocity :

The speed at which atmospheric drag matches the pull of gravity, resulting in a constant fall rate; a body falling at maximum acceleration. The typical freefall equilibrium velocity attained against air resistance is approximately 160 – 200 fps, or about 110 – 130 mph for the stable face-to-earth body position; but speeds as high as 300 miles per hour have been reached.

thermal :

A rising air current that’s caused by heating from the underlying surface.

thread through / thread-through :

A leg strap configuration on a parachute harness that uses a single piece of adjustable hardware, such that leg strap disconnection would require complete disassembly or “unthreading”; also called “step-through”. When donning or doffing this parachute harness, the jumper simply steps into or out of the connected legs straps.

three ring :

A parachute release mechanism connecting the risers to the harness. This cut-away release system, invented by Bill Booth in the late 1970s, utilizes three rings of separate size in a mechanical advantage mechanism. In its common configuration, pulling one cut-away handle will simultaneously release both main risers. It is a patented form of “single point release”, also available in a scaled-down “mini three ring” release version; and replaces the older style Capewell and Chrysalis releases.

throw-out :

A hand deployment method for parachute activation in which the pilot chute is stowed in a pouch on the belly (belly-band) or leg (ROL), or bottom of the container (BOC), and introduced manually into the airstream. A curved closing pin or equivalent locking device on the bridle is extracted as the jumper is separated from the pilot chute, opening the container and deploying the main canopy. A bridle tethers the pilot chute to the main canopy.

toggles :

Loops or cylindrical handles attached to the ends of the steering lines on a parachute canopy in order to facilitate their use; also called “steering toggles”. Toggles and lines are configured so they can be stowed in a partially down position to enhance the opening of the parachute.

track :

The body position or movements designed to achieve the maximum horizontal speed in freefall. The general term for the aerial maneuvers that skydivers use to laterally approach and depart other jumpers. Specifically, these versatile, face-to-earth body positions enable the skydiver to move tangentially or peripherally, forward or sideways, by the angle of the head, the retraction of arms or legs, or the extension of arms or legs. These same maneuvers, when extended into aerobatic routines, constitute the discipline of freestyle performance.

trim tabs :

A front riser pulley system for adjusting a ram-air canopy’s or airfoil’s angle of incidence or flight attitude.


Technical Standard Order (TSO-C23) is an FAA regulation, including National Aircraft Standard (NAS), requiring parachute manufacturers to comply with minimum performance standards and material product specifications to ensure safety; TSO compliance must be certified on a product display placard in order to be legally marketed.

turbulence :

Disturbed air that can adversely affect canopy flight and integrity. Also, the disorderly effect of irregular and inconsistent motions. Also, the haphazard secondary motions caused by eddies within a larger moving medium, as in the gusts and lulls of winds aloft in the atmosphere.

turf surf :

To run with the wind in ground effect; a sustained high-speed paraglide across and slightly above ground level, before using a flaring hook turn to land spectacularly.

turn around load :

The quick pick-up of jumpers into a plane that does not shut-down after landing, so as to immediately take-off for another jump run.

two-handled system :

Refers to a parachute harness and container operating system that uses separate handles (pud) for the canopy release and for reserve activation; as distinguished from a Single Operation System (SOS).

uncouple :

To release the connecting link between objects or persons; the mechanical disconnect or physical separation of a coupling; to unfasten or let go, as a glider uncoupled from a tow plane.

undercurrent :

An air current that flows below the upper or beneath the primary currents.

updraft :

The ascending flow or movement of air, or other rising gas.

uppers :

The upper winds, or the winds blowing at exit altitude, which are often much stronger and occasionally from a different direction than ground winds. Also called “winds aloft”.

upwash :

The slight updraft, or upward flow of air that’s redirected just prior to its reaching the leading edge of a rapidly moving airfoil.

upwind :

The direction from which the wind is blowing; toward or against the prevailing wind.


The United States Parachute Association is a non-profit skydiver’s membership organization offering guidance and assistance in training, competition, government relations, insurance, and other appurtenances. It originated in 1957 as “Parachute Clubs of America” (PCA), the coordinating body for autonomous and regional sport parachute clubs (SPC), and as a division of the National Aeronautic Association (NAA), it is the official representative of the Federation Aeronautique Internationale (FAI) for skydiving in the USA.

veer :

A change of direction, course, position, or attitude, as when turning aside, or shifting into the wind.

vortex :

A whirling mass of air, especially one in the form of a visible spiral, and operating with the force of suction, as a tornado.

waffle :

The vibratory effect of a canopy or airfoil during an abrupt brake or sustained flare, in which the leading edge trembles or flutters, and the entire surface may ripple or undulate, as the parachute attempts to resume flight. An effect similar to luff, but from a different cause.

waiver :

A liability release. Also, an exception to the regulations authorized by the USPA. [nb: not to be confused with “waver”: the quaking condition of frightened neophytes!]

wash :

To flow against, around, over, or through, as when currents affect passing crafts or vessels; also known as prop wash or jet stream (slipstream). Also, the rough or broken current (burble) behind a moving craft or vessel; awake or backwash.

water jump :

A freefall or parachute jump that terminates by intentionally landing on the surface of an “open body of water”.

wave off :

After break off and prior to deployment, a skydiver should check his surround, move away from other parachutists, and make a clearly defined arm motion to indicate to anyone nearby that he is about to open his parachute. A good wave off is essential to the avoidance of deployment collisions.


Wind Drift Indicator; being either a weighted foil or crepe paper streamer that’s thrown from the jump plane to estimate winds under canopy and to help determine the jump spot. The military will also use a smoke grenade as WDI, but the best indicator is a pathfinder on the DZ.

weights :

Many light- or underweight civilian skydivers wear a weighted vest to allow them to maintain a fast fall rate; but military parachutists, who almost always jump with equipment, do not have this problem.

wind drift indicator :

A device used to determine the amount and speed of wind drift which a descending parachute will experience on a particular drop zone (DZ) under conditions currently prevailing. The WDI is constructed as to descend at a rate comparable to a parachutist of average weight, or object of average payload, descending under a fully deployed main canopy of average specifications. Usually, the WDI is a weighted strip of foil or brightly colored crepe paper 10 inches wide by 20 feet long, but smoke grenades are also used.

wind line :

An imaginary line from the desired landing area, extending along the direction the wind is blowing to the point of release, or to the jump spot.

wind shear :

A dangerous condition in which the speed or direction of the wind changes abruptly. Also, the rate at which wind velocity changes from point to point in any given direction.

wing loading :

The ratio (ie: pounds per square foot) of weight borne by a wing or airfoil to its surface area; obtained by dividing the jumper’s exit weight in pounds by the square footage of the fully opened canopy. Excessive wing loading causes “blow-outs”, which can cause the canopy to fail as a decelerator.

wing suit :

A gliding jumpsuit designed with fabric membranes between the legs of the jumper and from each sleeve to the torso. Derived from jumpsuits designed with extra fabric pleated into the sleeves and legs, thus varying the amount of drag by adjusting the amount of fabric wing exposed when released by zippers prior to freefall exit.

wing wiper :

Slang for aviation support staff and ground crew, as used by Navy and Marine aviators since before WWII; also known as “penguin”.

wuffo :

Skydiver slang for people who don’t parachute; as derived from the groundling’s or landlubber’s most prevalent question: “Wuffo you jump outta dem planes?”! Also spelled “whuffo”. This term is considered “insensitive” by legs and other assorted landlocked sympathizers.

yo-yo :

An elevator-effect upon a deployed canopy (and the attached parachutist) generated by thermals and other turbulent or inconsistent air currents, especially when soaring over ice or fire, forest or sea, cliff or canyon.

zero-p :

Common slang for a type of fabric relatively impermeable to air; “zero-permeability”. The less air that flows through the fabric wing of a ram-air parachute, the more efficiently it flies.